The serpentine belt between two adjacent pulleys in an engine’s Front End Accessory Drive (FEAD) system is simplified as an axially moving viscoelastic string. Nonlinear dynamical equation is established for investigating the stability of the axially moving string subjected to parametric excitation resulted from tension and translation-speed oscillations. Galerkin method is used to discrete the nonlinear partial differential equations into a group of ordinary differential equations. Perturbation method is used for calculating the primary and secondary instability frequencies of the belt’s transverse vibration. An experiment was carried out for getting the angular velocity of the pulleys and the vibration of the belt in the FEAD system, and the parametric excitation frequencies of the belt’s transverse vibration were identified. The parametric excitation frequencies in the experiment agreed well with those of calculated results. Experiment results show that the instability of belt’s transverse vibration occurs in the regions of belt’s secondary resonant frequencies. When the tensile force of the belt increases, the regions of belt primary and secondary resonant frequencies under the parametric excitation also increase greatly.%以发动机前端附件驱动系统中两相邻轮带段为研究对象，将带简化成轴向运动的粘弹性弦线，建立轴向运动弦线在张力和带速的参数激励下的非线性动力学方程；采用Galerkin方法将非线性运动偏微分方程离散为一组常微分方程，并用摄动法计算引起带横向振动不稳定特性的主/次谐共振频率范围。介绍发动机前端附件驱动系统中轮的角速度和带横向振动的实验装置和测试方法，识别出引起带横向振动不稳定特性的参数激励频率范围，带横向振动不稳定特性的共振频率范围计算值与实验值具有较好的一致性。实验结果表明带参数激励下横向振动的不稳定特性主要发生在带的次谐共振频率范围内；带段伸缩张力幅值越大，带在参数激励下横向振动的主/次谐共振频率范围就越大。
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